This invention is concerned with surgical sponges and dressings and more specifically to an inexpensive disposable primary dressing for use in a hospital that most nearly approaches the advantageous characteristics of the more expensive dressing materials.
Conventional wound dressings in the form of sponges and the like can generally be divided into four major types or categories.
Plain gauze dressings are generally transfer types of dressings used either directly on a wound or indirectly over a non-adherent dressing. The primary function of this type dressing is to lift and transfer the blood and other exudates from the wound into a fluid holding reservoir, such as an abdominal pad.
Washed gauze dressings are used where a softer, more open mesh, bulkier sponge might be needed for transfer. Such dressings have been made to provide a sponge structure that when applied, supplies some gentle pressure and cushioning than unwashed gauze sponges, however, inherently the structure is not uniform in thickness and several plies have to be utilized to provide optimal pressure.
Another type of dressing in use today is a filled gauze sponge, which consists of one or two plies of unwashed gauze, an inner matrix of cotton or rayon fibers, and in some cases a layer of creped cellulose wadding used as an inner carrier. This type of dressing can be utilized as a small fluid reservoir for soaking up and holding limited amounts of exudate. It lacks the softness and bulk, and the ability to transfer exudates in the same amounts that can be achieved with washed gauze.
Finally, another type of sponge or dressing being used today is similar to the filled gauze sponge with the only difference being the replacement of the gauze cover with a nonwoven material. Dressings of this type have characteristics similar to filled gauze sponges, but have additional deficiencies, for example, the structure has decreased strength when wet as compared to gauze, and the existence of a chemical binder in nonwoven material can be potentially irritating to some patients. Also, some of this type sponge or dressing have an apertured nonwoven cover that not only adheres to the wound, but because the apertures are larger than the granulating tissue it covers, then this tissue tends to grow through the apertures and retards healing. This type dressing has the further problem that its transfer characteristics are poor due to the cellulose wadding filler.
A disposable surgical dressing is yet to be produced inexpensively that is absorbent, but has good fluid transfer properties; will not adhere to the wound; and, has good surface integrity so as to remain as "lint free" as possible.
Accordingly, it is an object of the present invention to provide an inexpensive disposable primary dressing for hospital use that has all of the advantages of the more expensive counterparts without their inherent disadvantages.
It is another object of this invention to produce a nonwoven dressing material that has high fabric volume per unit of weight, good imbibition of liquids and good surface integrity.
It is still another object of this invention to achieve the above-described characteristics in a nonwoven material by bulking a layered, thermally bonded material.